From e0f32f78e51b9989ee89f608fd0dd10e9c230652 Mon Sep 17 00:00:00 2001
From: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Tue, 17 Sep 2019 14:09:35 +0200
Subject: drm/kms: Duct-tape for mode object lifetime checks
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Git-commit: e0f32f78e51b9989ee89f608fd0dd10e9c230652
Patch-mainline: v5.4-rc1
References: bsc#1152472
commit 4f5368b5541a902f6596558b05f5c21a9770dd32
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Fri Jun 14 08:17:23 2019 +0200
drm/kms: Catch mode_object lifetime errors
uncovered a bit a mess in dp drivers. Most drivers (from a quick look,
all except i915) register all the dp stuff in their init code, which
is too early. With CONFIG_DRM_DP_AUX_CHARDEV this will blow up,
because drm_dp_aux_register tries to add a child to a device in sysfs
(the connector) which doesn't even exist yet.
No one seems to have cared thus far. But with the above change I also
moved the setting of dev->registered after the ->load callback, in an
attempt to keep old drivers from hitting any WARN_ON backtraces. But
that moved radeon.ko from the "working, by accident" to "now also
broken" category.
Since this is a huge mess I figured a revert would be simplest. But
this check has already caught issues in i915:
commit 1b9bd09630d4db4827cc04d358a41a16a6bc2cb0
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date: Tue Aug 20 19:16:57 2019 +0300
drm/i915: Do not create a new max_bpc prop for MST connectors
Hence I'd like to retain it. Fix the radeon regression by moving the
setting of dev->registered back to were it was, and stop the
backtraces with an explicit check for dev->driver->load.
Everyone else will stay as broken with CONFIG_DRM_DP_AUX_CHARDEV. The
next patch will improve the kerneldoc and add a todo entry for this.
Fixes: 4f5368b5541a ("drm/kms: Catch mode_object lifetime errors")
Cc: Sean Paul <sean@poorly.run>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reported-by: Michel Dänzer <michel@daenzer.net>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
Tested-by: Michel Dänzer <mdaenzer@redhat.com>
Cc: Michel Dänzer <michel@daenzer.net>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190917120936.7501-1-daniel.vetter@ffwll.ch
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
drivers/gpu/drm/drm_drv.c | 4 ++--
drivers/gpu/drm/drm_mode_object.c | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index c456c3d3def2..769feefeeeef 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -976,14 +976,14 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags)
if (ret)
goto err_minors;
+ dev->registered = true;
+
if (dev->driver->load) {
ret = dev->driver->load(dev, flags);
if (ret)
goto err_minors;
}
- dev->registered = true;
-
if (drm_core_check_feature(dev, DRIVER_MODESET))
drm_modeset_register_all(dev);
diff --git a/drivers/gpu/drm/drm_mode_object.c b/drivers/gpu/drm/drm_mode_object.c
index c355ba8e6d5d..6a23e36ed4fe 100644
--- a/drivers/gpu/drm/drm_mode_object.c
+++ b/drivers/gpu/drm/drm_mode_object.c
@@ -42,7 +42,7 @@ int __drm_mode_object_add(struct drm_device *dev, struct drm_mode_object *obj,
{
int ret;
- WARN_ON(dev->registered && !obj_free_cb);
+ WARN_ON(!dev->driver->load && dev->registered && !obj_free_cb);
mutex_lock(&dev->mode_config.idr_mutex);
ret = idr_alloc(&dev->mode_config.object_idr, register_obj ? obj : NULL,
@@ -104,7 +104,7 @@ void drm_mode_object_register(struct drm_device *dev,
void drm_mode_object_unregister(struct drm_device *dev,
struct drm_mode_object *object)
{
- WARN_ON(dev->registered && !object->free_cb);
+ WARN_ON(!dev->driver->load && dev->registered && !object->free_cb);
mutex_lock(&dev->mode_config.idr_mutex);
if (object->id) {
--
2.28.0